package demo4;

public class Computer {
    public void open() {
        System.out.println("打开电脑！");
    }
    public void close() {
        System.out.println("关闭电脑！");
    }
    public void useDevice(USB usb) {
        usb.openDevice();
        if(usb instanceof KeyBoard)
        {
            KeyBoard keyBoard = (KeyBoard) usb;
            keyBoard.input();
        }else if(usb instanceof Mouse) {
            Mouse mouse = (Mouse) usb;
            mouse.click();
        }
        usb.closeDevice();
    }

    public static void main(String[] args) {
        Computer computer = new Computer();
        computer.useDevice(new KeyBoard());
        System.out.println("===========");
        computer.useDevice(new Mouse());
    }
}
